About a week ago, I got a chance to fly the UCD with a more rearward CG than the 5.5" that I started out with. I haven't installed the cowl on the ST 90 yet. The GP motor mount that came with the UCD was swapped out for the next smaller size, which saved 2.5 ounces of nose weight. The ST 90 was moved back as far as it would go on the mount to push the CG back even farther.

With an APC 14x6, the UCD balanced at 6.0" back and flew better than the 5.5" CG. Then I used a lighter 14x6 wood Zinger and got the CG back near 6.5" which made the UCD even more to fly. At 6.5" back with a nearly empty fuel tank, it just barely begins showing the first signs of being tailheavy. At this point, it looks like my UCD will end up with the CG about 6.5" back.

The initial test flights had shown a need for some right thrust and I figured about 2 degrees would be a good place to start. Since I was swapping motor mounts, this was a good time to add the right thrust. That's when I discovered that my UCD has over 1 degree of left thrust built into the firewall. Therefore I ended up using a 3 degree Ernst thrust plate to get back to about 2 degrees of right thrust.

Now with the 6.5" CG and the 2 degrees of right thrust, my UCD is much easier to hover and throw around in 3D flight. Once I get the MCP figured out, I suspect the UCD is going to end up being one of my all time favorite planes!